// to cal z ^ (2^252 - 3)
func fePow22523(out, z *FieldElement) {
	var t0, t1, t2 FieldElement
	var i int

	FeSquare(&t0, z)	//2
	for i = 1; i < 1; i++ {
		FeSquare(&t0, &t0)
	}
	FeSquare(&t1, &t0)	//4
	for i = 1; i < 2; i++ {
		FeSquare(&t1, &t1)	//8
	}
	FeMul(&t1, z, &t1)	//9
	FeMul(&t0, &t0, &t1)	//11
	FeSquare(&t0, &t0)	//22
	for i = 1; i < 1; i++ {
		FeSquare(&t0, &t0)
	}
	FeMul(&t0, &t1, &t0)	//31
	FeSquare(&t1, &t0)
	for i = 1; i < 5; i++ {
		FeSquare(&t1, &t1)	//1f
	}
	FeMul(&t0, &t1, &t0)	//0x3ff denoted by 10 1
 	FeSquare(&t1, &t0)
	for i = 1; i < 10; i++ {
		FeSquare(&t1, &t1)
	}
	FeMul(&t1, &t1, &t0)	//20 1
	FeSquare(&t2, &t1)
	for i = 1; i < 20; i++ {
		FeSquare(&t2, &t2)
	}
	FeMul(&t1, &t2, &t1)	//40 1
	FeSquare(&t1, &t1)
	for i = 1; i < 10; i++ {
		FeSquare(&t1, &t1)
	}
	FeMul(&t0, &t1, &t0)	//50 1
	FeSquare(&t1, &t0)
	for i = 1; i < 50; i++ {
		FeSquare(&t1, &t1)
	}
	FeMul(&t1, &t1, &t0)	//100 1
	FeSquare(&t2, &t1)
	for i = 1; i < 100; i++ {
		FeSquare(&t2, &t2)
	}
	FeMul(&t1, &t2, &t1)	//200 1
	FeSquare(&t1, &t1)
	for i = 1; i < 50; i++ {
		FeSquare(&t1, &t1)
	}
	FeMul(&t0, &t1, &t0)	//250 1
	FeSquare(&t0, &t0)
	for i = 1; i < 2; i++ {
		FeSquare(&t0, &t0)
	}
	FeMul(out, &t0, z)	//2^252 - 3
}